Pre-expansion
With our continuous pre-expansion, polystyrene is performed with a continuous cycle in the first expansion. This is of great importance as the starting point for optimal manufacturing of foamed products. In the end the density of the raw material is decisive for the weight of any product you produce. For example: it is possible to produce a 200 ml drinking cup with a weight of 2 grams, while a weight of 1,5 grams is an option as well, using the same machine and moulds. We offer a wide range of pre-expanders with varying capacities.
The automatic processing cycle begins with the inlet of raw material into the expansion chamber through the dosing hopper.
The expanded material, coming out from the expansion chamber, will be discharged by gravity into the fluidized bed and dried by means of hot air blowing. From here the material will be conveyed to the storage silos. Machine control is made by a main electro-mechanical and digital panel.
A precise measuring and adjustable steam/air flow device in combination with a rockwool insulation cover of the expansion chamber assures a very cost effective use from the perspective of energy consumption.
THW VA 40 all-in-one
The set-up of the THW VA40 all-in-one pre-expander consists of a vertical cylindrical vessel operating at atmospheric pressure, with a limited temperature up to 100ºC. The raw material, together with the steam, is continuously transported to the bottom of the vessel by a screw feed system. The expanded particles then exit the machine through an opening at the top. The combination of the screw feed rate, steam pressure and the height of the overflow opening make it possible to control the density of the particles.
THW VA 160 combi
The set-up of the THW VA160 combi consists of a fluid bed dryer and a vertical cylindrical vessel operating at atmospheric pressure, with a limited temperature up to 100ºC. The raw material, together with the steam, is continuously transported to the bottom of the vessel by a screw feed system. The expanded particles then exit the machine through an opening at the top. The combination of the screw feed rate, steam pressure and the height of the overflow opening make it possible to control the density of the particles.
THW VA 300 combi
The set-up of the THW VA300 combi consists of a fluid bed dryer and a vertical cylindrical vessel operating at atmospheric pressure, with a limited temperature up to 100ºC. The raw material, together with the steam, is continuously transported to the bottom of the vessel by a screw feed system. The expanded particles then leave the machine through an opening at the top. The screw feed rate, steam pressure and the height of the overflow opening make it possible to control the density of the particles
